CN101000113B - Middle and high pressure guiding type water pressure reducing valve - Google Patents

Abstract

The invention is a medium- and high- pressure pilot water pressure reducing valve, mainly comprising main valve and pilot valve, where in the pilot valve is pilot valve seat, pilot valve core, pilot valve spring and regulating rod arranged in turn; the main valve body is made with water inlet and outlet, and internally equipped with valve sleeve, the valve sleeve is internally equipped with main valve core; and it is characterized in that: (1) when the pilot valve core cooperates with the pilot valve seat, two acute angle side-shaped orifices simultaneously play a throttling role; (2) the valve seat hole of the pilot valve seat is internally equipped with pilot valve damping plug screw; (3) the axis of the main valve core is made with connecting hole in which the main valve damping plug screw is arranged. On the premise of not increasing machining accuracy, it reduces valve leakage, improves gas corrosion resistance and pollution resistance, as well as stability, and can use sea and fresh water and other low viscosity fluids as working media.

Description

Medium and high pressure pilot-operated water pressure reducing valve

technical field

The invention belongs to hydraulic transmission components, and in particular relates to a medium-high pressure pilot-operated water pressure reducing valve, which is applied in a hydraulic transmission system using low-viscosity fluids such as sea and fresh water as medium.

Background technique

The water hydraulic transmission technology that directly uses sea and fresh water as the working medium has outstanding advantages such as environmental protection, flame retardant, and low cost. However, due to the strong corrosiveness, high density, low viscosity and high vaporization pressure of water, the traditional oil pressure reducing valve directly uses water as the working medium, which has large leakage, serious cavitation and wire drawing erosion, and poor stability. question. If it is used in polluted environments such as rivers and oceans, the sediment in the water will also severely erode and scrape the valve core and valve seat.

The existing DR-type pressure reducing valve with mineral oil as the working medium is mainly composed of a pilot valve and a main valve. The main valve of the valve adopts a slide valve structure, and the corrosion resistance and cavitation resistance of the material are poor. If the pressure reducing valve directly uses water as the working medium, there will be problems such as large leakage, serious corrosion and cavitation, so that the valve will fail quickly or cannot be used at all. At the same time, the sealing between the valve core and the valve sleeve is mainly ensured by reducing the gap, so the filtration accuracy of the medium is very high. For the marine polluted environment or the situation where the water contains sand, the valve core is easy to be stuck and cause valve failure. failure. In addition, since the water hammer phenomenon is serious when water is used as the working medium, if the valve is directly used as the working medium, there is also the problem of poor stability.

Contents of the invention

The present invention proposes a medium and high pressure pilot-operated water pressure reducing valve. Aiming at the low viscosity of the water medium, cavitation wire drawing and severe pressure shock, it proposes corresponding solutions from the aspects of structural type and material selection, and overcomes the existing pilot-operated pressure reducing valve. Pressure reducing valves have problems such as large leakage, serious corrosion and cavitation.

The present invention proposes a medium-high pressure pilot-operated water pressure reducing valve, which is composed of a main valve and a pilot valve connected. ;The pilot valve seat has a valve seat hole in the axial direction, and the pilot valve core constitutes the pilot valve throttle port; the main valve is a slide valve, and the valve body is equipped with a water inlet and a water outlet. There are holes respectively connected to the water inlet and outlet of the valve body, and a small hole is opened at the end of the valve sleeve close to the water outlet of the valve body; the main valve core is installed in the valve sleeve, and the main valve core and the valve sleeve are paired to form a friction pair and constitute the main body. A valve orifice; characterized in that:

The end of the pilot valve seat is provided with an undercut groove whose diameter is larger than the diameter of the valve seat hole. flow effect;

The pilot valve damping screw plug is arranged in the valve seat hole of the pilot valve seat;

The central axis of the main valve core is provided with a communication hole, and a main valve damping screw plug is arranged in the communication hole; combined sealing rings are respectively installed at both ends of the main valve core.

The present invention adopts the form of two-stage throttling at the throttle port of the pilot valve, which prevents or weakens the occurrence of cavitation and wire drawing at the valve port; for the characteristics of low viscosity and small damping of the water medium, before the inlet of the pilot valve The damping hole is set to reduce the pressure impact and oscillation of the main valve core caused by the pressure change of the water inlet and outlet, and improve the stability of the valve; the main valve adopts the combination of the valve core, valve seat and valve sleeve, so that it is convenient Different materials are selected for the cavitation and wire drawing erosion resistance of the parts. The hardness of the valve core is increased by heat treatment, so as to improve its anti-cavitation ability. The combined sealing ring is installed on the main valve core to play an auxiliary sealing role, which basically prevents the leakage in the tiny gap between the valve core and the valve body and the resulting wire drawing erosion, and at the same time reduces the requirements on the processing accuracy of the valve and the processing cost , and due to the increase of this gap, the possibility of the valve core being stuck by solid particles entering the valve is reduced, thereby enhancing the anti-pollution ability of the valve.

Compared with the oil pressure valve, the valve reduces the leakage of the valve without significantly improving the processing accuracy of the valve; improves the cavitation resistance and anti-pollution ability of the valve; at the same time improves the stability of the valve, and can use sea (fresh) water Such as low viscosity fluid as the working medium. Within its effective working pressure range, the outlet pressure _p2 is relatively stable when the inlet pressure _p1 changes. When the inlet pressure remains constant, if the flow through the valve changes, the outlet pressure _p2 will also remain basically stable.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the present invention;

Figure 2 is a partial enlarged view of the throttle port of the pilot valve.

Detailed ways

Figure 1 shows an embodiment of the present invention, in the figure, valve body 1, outlet sealing ring 2, main valve damping screw plug 3, main valve core 4, valve sleeve sealing ring 5, combined sealing ring 6, valve sleeve 7 , spring seat 8, valve core sealing ring 9, main valve spring 10, pilot valve body 11, screw plug 12, screw plug sealing ring 13, bolt 14, spring washer 15, pilot valve seat 16, pilot valve damping screw plug 17 , Pilot valve body sealing ring 18, pilot valve core 19, leakage port sealing ring 20, pilot valve spring 21, adjusting rod 22, adjusting rod sealing ring 23, lock nut 24, adjusting handle 25, oil drain port 26, main valve Core right chamber 27, main valve throttle port 28, main valve core left chamber 29.

As shown in Figure 1, as an example, the rated working pressure of the valve is 21 MPa, the outlet working pressure is 10-16 MPa, and the rated flow rate is 40 L/min. By adjusting the handle 25, by compressing the pilot valve spring 21, different opening pressures of the pilot valve can be adjusted, thereby adjusting the stable pressure of the outlet. The main valve core 4 and the valve sleeve 7 are paired to form a friction pair, and constitute the main valve throttle port 28 . Combined sealing rings 6 are respectively installed on the main valve core 4 . A communication hole is opened in the center of the main valve core 4, and a main valve damping screw plug 3 is arranged in the communication hole. The outlet pressure of the main valve enters the right cavity 27 of the main valve core through the communication hole and the damping hole of the main valve damping screw, so that both ends of the main valve are under pressure. The pressure medium entering the right cavity 27 of the main valve core also acts on the pilot valve spool through the damping hole of the pilot valve damping plug 17 .

The inlet pressure p ₁ is decompressed by the throttle port 28 of the main valve and becomes the outlet pressure p ₂ , the outlet pressure enters the left chamber of the main valve core 4 through the small hole at the left end of the valve sleeve 7 , and then passes through the upper center of the main valve core. The communication hole and the main valve damping screw plug 3 enter the right cavity 27 of the main valve core, pass through the pilot valve damping screw plug 17 in the pilot valve seat 16, and act on the pilot valve core 19. When the outlet pressure is lower than the set pressure, the pilot valve port is closed, and there is no oil flow in the damping hole of the main valve damping plug 3, the pressure at the left and right ends of the main valve core 4 is equal, and the main valve is under the spring force of the main valve spring 10. It is in the leftmost position under the action of the main valve throttle port 28 fully open, and does not have the decompression effect, p ₂ ≈ _{p 1} . When the outlet pressure exceeds the set pressure, the outlet part of the liquid flows out through the damping hole of the pilot valve damping screw plug 17, the pilot valve port, and the oil drain port 26. The damping hole of the main valve damping screw plug 3 has liquid passing through, so that the left cavity 29 of the main valve core and the right cavity 27 of the main valve core generate a pressure difference. When the power and friction are combined, the main valve moves to the right, so that the throttle port (decompression port) 28 is closed, and the throttling loss increases until the main valve core stabilizes at a certain equilibrium position. At this time, the outlet pressure _p2 depends on The pressure value set by the pilot valve spring.

If the inlet pressure _p1 increases, the outlet pressure _p2 also increases, the main spool 4 moves to the right, the orifice decreases, _p2 decreases again, the main spool 4 is in balance at the new position, and the outlet pressure p ₂ remains essentially unchanged; and vice versa.

Figure 2 is a partial enlarged view of the throttle port of the pilot valve. Due to the large pressure difference and the high flow rate of the water flow at the pilot valve port, there are serious cavitation and wire drawing phenomena. In order to solve this problem, a two-stage throttling structure is adopted at the pilot valve port, that is, at the end of the pilot valve seat 16, in addition to the valve seat hole, an undercut groove with a diameter larger than the valve seat hole is added, so that a throttling The part forms two sharp edges, and when the pilot valve core 19 is paired with the pilot valve seat 16, there are two sharp-edged throttle openings at one throttling position to play a throttling role at the same time. This structure achieves the effect of reducing cavitation and wire drawing erosion by reducing the flow velocity of the pilot valve port. The pilot valve damping screw plug 17 is arranged before the pilot valve inlet, so as to reduce the impact and vibration of the main valve core. If there is no damping hole of the pilot valve damping plug, the pilot valve will suddenly open when the outlet pressure reaches its set pressure, and the pressure difference between the two ends of the main valve will suddenly increase, making it quickly move to the right, reducing the pressure reducing section. The flow area of the orifice increases, the pressure loss increases, the outlet pressure decreases, the pilot valve closes suddenly, the main valve core moves to the left under the action of the spring, the pressure reduction orifice is increased, and the outlet pressure rises. Repeatedly, the main valve will be in a state of reciprocating oscillation, resulting in extremely unstable outlet pressure of the valve. After adding a damping hole before the inlet of the pilot valve, when the outlet pressure reaches the set pressure of the pilot valve, the main valve will not move too fast, thereby avoiding its oscillation in the valve sleeve.

Claims (1)

1. A medium and high pressure pilot-operated water pressure reducing valve, which is composed of a main valve and a pilot valve connected. The pilot valve is a cone valve. The pilot valve body is sequentially equipped with a pilot valve seat, a pilot valve core, a pilot valve spring and an adjustment rod; The pilot valve seat has a valve seat hole in the axial direction, and the pilot valve core forms a pilot valve throttle port; the main valve is a slide valve, and the valve body is equipped with a water inlet and a water outlet. There are holes connecting the water inlet and outlet of the valve body respectively, and a small hole is opened at the end of the valve sleeve near the water outlet of the valve body; the main valve core is installed in the valve sleeve, and the main valve core and the valve sleeve are paired to form a friction pair and constitute the main valve. Throttle; characterized in that: The end of the pilot valve seat is provided with an undercut groove whose diameter is larger than the diameter of the valve seat hole. flow effect; The pilot valve damping screw plug is arranged in the valve seat hole of the pilot valve seat; The central axis of the main valve core is provided with a communication hole, and a main valve damping screw plug is arranged in the communication hole; combined sealing rings are respectively installed at both ends of the main valve core.

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